Article for assisting in toilet training

ABSTRACT

A toilet training article in the form of a toilet training pad containing an effervescent agent is disclosed. The toilet training pad, which may be an insertable pad or integrated directly into an undergarment, contains an effervescent agent which releases gas upon being contacted by urine. The effervescent agent may be in the form of a compound containing a substantially inert gas, or may be a combination of compounds that, upon being contacted by urine, produce a gas.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional patent application of patentapplication Ser. No. 10/383,125 filed on Mar. 6, 2003, which is adivisional patent application of patent application Ser. No. 09/696,747filed on Oct. 25, 2000, which has issued as U.S. Pat. No. 6,576,810.

BACKGROUND OF THE INVENTION

The present invention relates to an article for assisting humans,particularly children, in toilet training. More specifically, thepresent invention relates to an article in the form of a pliable padcontaining an effervescent agent or material which when worn facilitatesthe toilet training process by providing a release of gas next to theskin of the wearer during and/or after urination occurs to alert orsignal the wearer.

Disposable absorbent training pants are useful in toilet trainingchildren. Typically, these undergarments are similar to washable, clothunderwear in how they are put on and worn, yet also provide an absorbentfunction like diapers to draw and retain urine away from the skin of thewearer. Training pants provide a child undergoing toilet training withan undergarment which eases the transition from diapers to washable,cloth underwear as they become more confident in their ability to usethe toilet independently.

In order to learn to use the toilet independently, a child must firstrecognize when urination has occurred so that this bodily function maybe controlled. This recognition can represent a substantial hurdle inthe training process as urination may often occur during an activitythat distracts the child sufficiently so that the child does not noticeurination. Also, a child's ability to recognize when urination occursmay be hampered by the improved performance of disposable absorbentundergarments which quickly draw and retain urine away from the wearer'sskin after an insult occurs.

Many believe that a child must feel the sensation of wetness on the skinafter urination in order to facilitate awareness of this bodily functionand promote timely use of the toilet so as to avoid the uncomfortablefeeling which otherwise follows. Although this belief is embraced bymany, such practice may expose a child to increased risk of skinirritations and rashes caused by prolonged and repeated contact withurine.

Several attempts have been made at providing toilet training aids whichalert a child that urination has occurred. For example, pads adapted forreleasable attachment to the crotch and/or buttocks region of adisposable toilet training pant, diaper or other undergarment andincluding a temperature change member and/or a dimensional change memberwhich provide a temperature change or dimensional change sensation whencontacted with urine to alert the child wearing the undergarment thaturination has occurred have been fabricated. Also absorbent articles aredisclosed that when first insulted, have a high initial surface moisturevalue or wet feel to alert the child that urination has occurred. Thisinitial wetness lasts only a short time after which the surface moisturevalue drops to a lower level resulting in a drier feeling to the childand increased comfort.

Although there has been substantial progress in toilet training aids,there continues to be a need for simple, effective articles that alertchildren that urination has occurred.

SUMMARY OF THE INVENTION

The present invention concerns a toilet training article which alertsthe wearer that urination has occurred. The toilet training article isin the form of a pad worn in conjunction with an undergarment. The padmay be made an integral part of the undergarment, or may be adapted forreleasable or permanent attachment to the undergarment by a purchaser.The pad contains an effervescent agent or combination of agents thatalerts the wearer that urination has occurred by releasing gas andcausing a mild concussive (i.e., “popping,” “crackling,” “bubbling” or“fizzing”) sensation on or next to the wearer's skin upon urination.This may be accomplished, if desired, without trapping moisture againstthe skin of the wearer. The present invention can be used in a varietyof absorbent undergarments.

Briefly, therefore, the present invention is directed to an article foruse in conjunction with an undergarment in the form of a pad comprisinga pliable substrate and an effervescent agent disposed on the substrate.The effervescent agent comprises a mixture of an acid compound and abase compound that, upon being contacted with urine, react and produce agas. The substrate has a body side face and an outside face, the bodyside face facing the skin of the wearer when the article is worn. Theeffervescent agent is disposed on the substrate in a manner such thatwhen the pad is wetted with urine, the effervescent agent releases a gasto alert the wearer of urination.

The invention is further directed to an article for use in conjunctionwith an undergarment in the form of a pad comprising a pliable substrateand an effervescent agent disposed on the substrate. The effervescentagent comprises a mixture of an acid compound and a base compound that,upon being contacted with urine, react and produce a gas. The substratehas a body side face and an outside face, the body side face facing theskin of the wearer when the article is worn. The effervescent agent hasa size of from about 5 micrometers to about 40 micrometers, and theeffervescent agent is disposed on the substrate in a manner such thatwhen the pad is wetted with urine, the effervescent agent releases a gasto alert the wearer of urination.

Other embodiments and features of this invention will be in partapparent and in part pointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a pliable toilet training pad inaccordance with the present invention.

FIG. 2 is a perspective view of a disposable toilet training article inaccordance with the present invention, which includes a pliable toilettraining pad.

Corresponding reference characters indicate corresponding partsthroughout the drawings.

DEFINITIONS

Within the context of this specification, each term or phrase below willinclude the following meaning or meanings:

(a) “Bonded” refers to the joining, adhering, connecting, attaching, orthe like, of two elements. Two elements will be considered to be bondedtogether when they are bonded directly to one another or indirectly toone another, such as when each is directly bonded to intermediateelements.

(b) “Disposable” refers to articles which are designed to be discardedafter a limited use rather than being laundered or otherwise restoredfor reuse.

(c) “Film” refers to a thermoplastic film made using a film extrusionand/or foaming process, such as a cast film or blown film extrusionprocess. The term includes apertured films, slit films, and other porousfilms which constitute liquid transfer films, as well as films which donot transfer liquid.

(d) “Hydrophilic” describes fibers or the surfaces of fibers which arewetted by the aqueous liquids in contact with the fibers. The degree ofwetting of the materials can, in turn, be described in terms of thecontact angles and the surface tensions of the liquids and materialsinvolved. Equipment and techniques suitable for measuring thewettability of particular fiber materials or blends of fiber materialscan be provided by a Cahn SFA-222 Surface Force Analyzer System, or asubstantially equivalent system. When measured with this system, fibershaving contact angles less than 90 are designated “wettable” orhydrophilic, while fibers having contact angles greater than 90 aredesignated “nonwettable” or hydrophobic.

(e) “Integrated” is used to refer to various portions of a singleunitary element rather than separate structures bonded to or placed withor placed near one another.

(f) “Layer” when used in the singular can have the dual meaning of asingle element or a plurality of elements.

(g) “Liquid impermeable,” when used in describing a layer or multi-layerlaminate means that a liquid, such as urine, will not pass through thelayer or laminate, under ordinary use conditions, in a directiongenerally perpendicular to the plane of the layer or laminate at thepoint of liquid contact. Liquid, or urine, may spread or be transportedparallel to the plane of the liquid impermeable layer or laminate, butthis is not considered to be within the meaning of “liquid impermeable”when used herein.

(h) “Liquid permeable” refers to a material present in one or morelayers, such as a film, nonwoven fabric, or open-celled foam, which isporous, and which is water permeable due to the flow of water and otheraqueous liquids, such as urine, through the pores. The pores in the filmor foam, or spaces between fibers or filaments in a nonwoven web, arelarge enough and frequent enough to permit leakage and flow of liquidwater through the material.

(i) “Meltblown” refers to fibers formed by extruding a moltenthermoplastic material through a plurality of fine, usually circular,die capillaries as molten threads or filaments into converging highvelocity heated gas (e.g., air) streams which attenuate the filaments ofmolten thermoplastic material to reduce their diameter, which may be tomicrofiber diameter. Thereafter, the meltblown fibers are carried by thehigh velocity gas stream and are deposited on a collecting surface toform a web of randomly dispersed meltblown fibers. Such a process isdisclosed for example, in U.S. Pat. No. 3,849,241 to Butin et al.Meltblown fibers are microfibers which may be continuous ordiscontinuous, are generally smaller than about 0.6 denier, and aregenerally self bonding when deposited onto a collecting surface.Meltblown fibers used in the present invention are preferablysubstantially continuous in length.

(j) “Nonwoven” and “nonwoven web” refer to materials and webs ofmaterial which are formed without the aid of a textile weaving orknitting process.

(k) “Pliable” refers to materials which are compliant and which willreadily conform to the general shape and contours of the wearer's body.

(l) “Polymers” include, but are not limited to, homopolymers,copolymers, such as for example, block, graft, random and alternatingcopolymers, terpolymers, etc. and blends and modifications thereof.Furthermore, unless otherwise specifically limited, the term “polymer”shall include all possible geometrical configurations of the material.These configurations include, but are not limited to, isotactic,syndiotactic and atactic symmetries.

(m) “Spunbond” refers to small diameter fibers which are formed byextruding molten thermoplastic material as filaments from a plurality offine capillaries of a spinnerette having a circular or otherconfiguration, with the diameter of the extruded filaments then beingrapidly reduced as by, for example, in U.S. Pat. No. 4,340,563 to Appelet al., and U.S. Pat. No. 3,692,618 to Dorschner et al., U.S. Pat. No.3,802,817 to Matsuki et al., U.S. Pat. Nos. 3,338,992 and 3,341,394 toKinney, U.S. Pat. No. 3,502,763 to Hartmann, U.S. Pat. No. 3,502,538 toPeterson, and U.S. Pat. No. 3,542,615 to Dobo et al., each of which isincorporated herein in its entirety by reference. Spunbond fibers aregenerally continuous and often have average deniers larger than about0.3, more particularly, between about 0.6 and about 10.

(n) “Superabsorbent” refers to a water-swellable, water-insolubleorganic or inorganic material capable, under the most favorableconditions, of absorbing at least about 15 times its weight and, moredesirably, at least about 30 times its weight in an aqueous solutioncontaining 0.9 weight percent sodium chloride. The superabsorbentmaterials can be natural, synthetic and modified natural polymers andmaterials. In addition, the superabsorbent materials can be inorganicmaterials, such as silica gels, or organic compounds such ascross-linked polymers.

(o) “Surface” includes any layer, film, woven, nonwoven, laminate,composite, or the like, whether pervious or impervious to air, gas,and/or liquids.

(p) “Surge Layer” refers to a layer typically comprised of nonwovenmaterials that can absorb a large stream or gush of liquid and releaseit slowly into another layer or layers.

(q) “Thermoplastic” describes a material that softens when exposed toheat and which substantially returns to a nonsoftened condition whencooled to room temperature.

(r) “Three dimensional” refers to a garment similar to underwear, shortsor pants in that it has continuous leg and waist openings that arebounded by material of which the garment is made. The garment may or maynot have manually tearable seams.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with the present invention, it has been discovered that aneffervescent agent can be strategically positioned in a child's toilettraining pant or other undergarment such that upon urination theeffervescent agent releases gas to alert the wearer that urination hasoccurred. The wearer may be alerted of the urination either throughfeeling the release of the gas on the skin, or by feeling a mildconcussive (i.e., “popping,” “crackling,” “bubbling” or “fizzing”)sensation on the skin, or a combination thereof. The toilet trainingarticle in accordance with the present invention can be used inconjunction with an disposable or non-disposable absorbent undergarmentto alert the wearer that urination has occurred while reducing potentialadverse effects of prolonged contact between the skin and voided urine.Although discussed primarily in the context of toilet training ofchildren, it should be understood that the present invention and itsfunction are also applicable as an adult personal care product such asin absorbent incontinence undergarments and the like.

Referring to FIG. 1, there is shown a pliable toilet training pad 30 inaccordance with the present invention. The toilet training pad comprisesa pliable substrate having a body side 32 and an outer side 34. The bodyside faces the skin of the wearer during wear, generally in the crotchand/or buttocks region, while the outer side faces away from the skin ofthe wearer. As illustrated in FIG. 1, the toilet training pad is oflayered construction and comprises a liner layer 36 and an absorbentcore layer 38. Although illustrated in FIG. 1 with layered constructionhaving two distinct, separate layers, and discussed herein primarily ashaving a liner and an absorbent core layer, it should be recognized thatthe toilet training pad of the present invention could be comprised of asingle layer substrate comprised of, for example, a liner, or may becomprised of numerous different layers which may vary in absorbentcapacity, thickness, material of construction, intended purpose, etc.Again referring to FIG. 1, outer side 34 may optionally containattachment means 40 for releasably attaching the toilet training pad toan undergarment, such as a disposable undergarment. An effervescentagent 42 is typically disposed on at least a part of the outside face 34of the toilet training pad such that upon urination, the effervescentagent releases gas in close proximity to the skin of the wearer to alertthe wearer that urination has occurred. Alternatively, or in addition,the effervescent agent may be located on at least part of the insideface or on or between one or more other layers of the pad as describedbelow.

The effervescent agent-containing toilet training pad of the presentinvention may be a single layer or may be of layered construction andmay be comprised of a plurality of fibers which may be woven, nonwoven,or a combination thereof. The fibers may be bi-component, hollow,natural or synthetic, or a combination thereof, and may be hydrophilicor hydrophobic in nature, and may be, for example, a short staple fiberor a longer more continuous fiber generally found in meltblown andspunbond webs. Other suitable webs include bonded carded webs, air laidwebs, wet laid webs, solution spun webs, porous films and generally anyporous webs which have sufficient strength to be used as a liner forpersonal care absorbent products. Polyolefins, polyesters, cellulosics,polyacetates, and polyacrylate thermoplastics are some examples ofpolymers from which the fibers can be formed. One or more layers of thetoilet training pad of the present invention may be liquid permeable andcomprised of, for example, a liquid permeable film, tissue, fabric, orthe like. One or more layers may also be liquid impermeable andcomprised of, for example, a web or sheet of plastic film such aspolyethylene, polypropylene, polyvinyl chloride, or similar material, ora nonwoven, fibrous web which has been suitably constructed and arrangedto be substantially liquid impermeable. The toilet training pad of thepresent invention may also contain one or more superabsorbent and/orsurge layers, or other layers which may be used alone or in combinationwith one or more layers described above.

As used herein, an effervescent agent means a material or compound thatis capable of rapidly releasing gas upon contact with urine to cause amild concussive or “popping” or “% crackling” sensation on a wearer'sskin or a mixture of compounds that, when contacted or mixed togetherand wetted with urine, produces a gaseous product and a “bubbling” or“fizzing” feeling on the wearer's skin. Thus, the effervescent agent maybe a solid material (e.g., a crystal matrix) in which a pressurized gasis trapped and that gas is released upon contact with voided urine.Alternatively, the effervescent may be a mixture of compounds which whencontacted or mixed together and wetted with urine, react and produce anon-toxic, gaseous reaction product without releasing a substantialamount of heat. The effervescent agents used in accordance with thepresent invention are substantially non-hazardous when contacted withhuman skin.

In one embodiment of the present invention, the effervescent agent maybe a urine soluble solid material produced in such a manner such that apressurized gas is trapped within cells located in the solid material.When the solid material having pressurized gas containing cells iscontacted with urine, it begins to dissolve and the pressurized gas isreleased from the cells creating a noticeable sensation on the wearer'sskin which may be felt as a rush of gas over the skin or as a “popping,”“crackling” “bubbling” or “fizzing” sensation due to the release of thegas. This sensation, whether by a rush of gas or by a “popping,”“crackling,” “bubbling” or “fizzing” sensation alerts the wearer to theurination. In this embodiment, the effervescent agent may comprise asugar compound such as a mono-saccharide, di-saccharide, orpoly-saccharide which has been infused with a gas that is substantiallynon-reactive with human skin such as carbon dioxide, air, nitrogen,argon, helium, etc. Specific examples of saccharides that can be used inaccordance with the present invention to create an effervescent agentinclude glucose, fructose, sucrose, lactose, maltose, dextrin,cyclodextrin, and the like, alone or in combination. Also, a mixture ofsucrose with corn syrup (containing glucose, maltose, and dextrin) canbe used in accordance with this embodiment of the present invention toprovide a gas-containing effervescent agent. Other examples of compoundswhich are capable of being prepared in such as manner as to trappressurized gas in cells include, for example, water soluble compoundssuch as salts and alkali halides and alkaline earth metal halides.Specific salts useful in the present invention include, for example,sodium chloride, potassium chloride, potassium bromide, lithiumchloride, cesium chloride, and the like. Typically, the cells have adiameter from about 5 micrometers to about 100 micrometers.

The non-reactive gas can be infused into the cells of the urine-solublesolid material to produce an effervescent agent useful in the presentinvention by first heating the starting material such as a sugar in asmall amount of water until the material is dissolved. After dissolutionof the material, the water is evaporated off leaving the material in amolten state. The molten material is then gasified by introducing aninert gas, such as carbon dioxide, at a superatmospheric pressure into aclosed vessel containing the molten material. The melt is agitatedduring gasification to ensure intimate contact between the moltenmaterial and the gas. Pressures of, for example, between about 50 psig(340 kPa) and about 1000 psig (6890 kpa) may be utilized to infuse thegas into the material. After gas infusion, the molten material isallowed to solidify while maintained in the closed vessel to produce aneffervescent agent in accordance with the present invention. Thisprocedure of producing a gas containing solid material is fully setforth in U.S. Pat. No. 4,289,794, which is hereby incorporated byreference. The above procedure can produce effervescent agentscontaining cells of pressurized gas from about 50 psig (340 kPa) toabout 900 psig (6200 kPa) which, when exposed to urine, allow therelease of the trapped gas causing a mild concussive effect or a“popping” or “crackling” next to the skin to alert the wearer thaturination has occurred. Typically, from about 0.1 grams to about 15grams of gas-containing effervescent agent are incorporated into thetoilet training pad of the present invention to alert the wearer thaturination has occurred.

In another embodiment of the present invention, an effervescent agentfor use in or on a toilet training pad can be comprised of a mixture ofcompounds, such as an acid and a base, that when wetted with urine,react and produce a gaseous product and the wearer is alerted to havingurinated through a “bubbling” or “fizzing” sensation on the skin. Theeffervescent agent could be in the form of a mixture of acid powders andbase powders, liquid acids and liquid bases, or combinations thereof.The solid acids and bases can be introduced neat or in microencapsulatedform into or onto the toilet training pad. Typically, if a liquid acidor base is utilized, it will be in microencapsulated form. One skilledin the art will recognize that the acids and bases utilized should besubstantially non-reactive with each other until wetted with urine.

In a particular embodiment, the acid and base are separatelyencapsulated into microencapsulated shells. A combination ofencapsulated shells containing acid and encapsulated shells containingbase are then introduced into or onto the toilet training pad of thepresent invention. It will be recognized by one skilled in the art thatwith some acid/base combinations it may be possible to first mix theacid and base together and then introduce the mixture into anencapsulated shell which can be introduced into a pad in accordance withthe present invention. In a separate embodiment, the acid and base aredispersed neat into or onto the toilet training pad of the presentinvention. It will also be recognized by one skilled in the art that acombination of encapsulated and neat acids and bases could be utilized.Any combination of compounds, such as an acid and a base, that issubstantially non-reactive with each other until wetted with water orurine and that react to form at least one non-toxic gaseous product uponwetting may be utilized as an effervescent agent in accordance with thepresent invention. One skilled in the art will recognize that both acidstrength and base strength may impact the amounts of acid and/or baseutilized to form the effervescent agent. One skilled will also recognizethat acid/base reactions are typically exothermic in nature and as suchcare should be taken to select appropriate acids and bases inconsideration of the amount of heat produced by the reaction in closeproximity to the skin of the wearer. Typically, the resulting acid/basemixture in the presence of the urine should have a resulting pH of fromabout 4.5 to about 7.5 to avoid skin damage. One skilled in the art willrecognize that a buffering agent could be utilized in combination withthe acid/base combination to help control the resulting pH of theacid/base mixture in the urine. One skilled in the art will alsorecognize that appropriate stoichiometric amounts of acids and baseswould need to be utilized to obtain a mixture that when wetted withurine will produce a pH in the above range. One example of a suitableacid/base combination is shown in equation (1)NaHCO₃+KHC₄H₄O₆----->KNaC₄H₄O₆+H₂O+CO₂  (1)

In equation (1), sodium bicarbonate and potassium bitartrate react inthe presence of a liquid (urine) to form carbon dioxide gas andby-products. The production of the carbon dioxide gas alerts the wearerof the pad containing the acid and base that urination has occurred.

Another example of a suitable acid/base combination is shown in equation(2):NaAl(SO₄)₂+3NaHCO₃------->Al(OH)₃+2Na₂SO₄+3CO₂  (2)

In equation (2), sodium aluminum sulfate and sodium bicarbonate react inthe presence of liquid (urine) to form carbon dioxide gas andby-products. Other acids that can be used in combination with sodiumbicarbonate to produce an effervescent agent in accordance with thepresent invention include ascorbic, lactic, glycolic, malic, tartaric,and fumaric. When mixed with sodium bicarbonate and contacted withurine, these acids produce carbon dioxide gas. This gas production canalert the wearer that urination has occurred.

The effervescent agents utilized in the present invention may beintroduced directly into or onto a face of the toilet training pad asdiscussed below, or alternatively, first encapsulated into a shellmaterial which releases the effervescent agent when wetted with urine.The microencapsulated shell is constructed of a material such that itwill release the effervescent agent upon contact with urine and allow itto produce gas to alert the wearer that urination has occurred. Theurine may cause the shell material to solubilize, disperse, swell,disintegrate, or may be urine permeable such that it disintegrates ordischarges the effervescent agent upon contact with urine. Suitableshell materials include cellulose-based polymeric materials (e.g., ethylcellulose), carbohydrate-based materials (e.g., starches and sugars) andmaterials derived therefrom (e.g., dextrins and cyclodextrins) as wellas other materials compatible with human tissues. The microencapsulationshell thickness may vary depending upon the effervescent agent utilized,and is generally manufactured to allow the encapsulated effervescentagent to be covered by a thin layer of encapsulation material, which maybe a monolayer or thicker laminate, or may be a composite layer. Themicroencapsulation layer should be thick enough to resist cracking orbreaking of the shell during handling or shipping of the product orduring wear which would result in breakage of the encapsulationmaterial. The microencapsulation layer should also be constructed suchthat humidity from atmospheric conditions during storage, shipment, orwear will not cause a breakdown of the microencapsulation layer.

Effervescent agents, whether in neat or microencapsulated form, that areapplied directly into or onto the toilet training pad can be located orbe of a size such that the wearer is not cannot feel the encapsulatedshell or solid against the skin prior to urination. Solid effervescentagents utilized neat may be introduced directly into the fabric of theliner, absorbent core, superabsorbent layer, or another layer and hencenot have direct skin contact prior to urination. Neat effervescentagents and microencapsulated shells typically have a size from about 5micrometers to about 40 micrometers, preferably from about 20micrometers to about 35 micrometers.

The effervescent agents of the present invention, either in neat form,in microencapsulated form or a combination of both neat andmicroencapsulated form, are typically introduced into the toilettraining pad of the present invention within or beneath the liner. Theeffervescent agent may be introduced beneath the liner and remain loosebetween the liner and a subsequent layer such as an absorbent core,surge layer, or other layer comprising the toilet training pad.Alternatively, if the toilet training pad of the present inventioncomprises solely a liner or a single layer, the effervescent agent istypically introduced into the material itself or onto the outer side ofthe liner which faces away from the wearer. In a particular embodiment,the effervescent agent may be introduced into or onto other layers of atoilet training pad such as a surge layer, a transfer layer, a tissuelayer, a superabsorbent layer or another layer as the toilet trainingpad may be comprised of numerous layers.

In a particular embodiment, the effervescent agent of the presentinvention can be placed onto or into the toilet training pad and the padpositioned such that the effervescent agent is present in the crotchregion of the wearer. Because the crotch region is the area of the bodywhere the fluid is produced, the wearer will be alerted rapidly uponurination as the urine will rapidly induce the effervescent agent torelease/produce a gas. Further, the crotch region contains a largenumber of nerve endings which can be stimulated by the release of gas bythe effervescent agent upon urination. In another embodiment, theeffervescent agent and toilet training pad can be located in thebuttocks area. In another embodiment, the effervescent agent and pad maybe located in both the crotch area and the buttocks area for maximumsensation.

Although the specific effervescent agent utilized may effect the overallsensation felt by the wearer upon urination, the amount of sensationfrom the gas released by the effervescent agent is typically a directresult of the amount of effervescent agent utilized. A sufficient amountof effervescent agent should be utilized such that the wearer can feel aconcussive affect or a “bubbling,” “popping,” or “crackling” feeling dueto the release of gas in the crotch, buttocks, or crotch and buttocksregions of the body.

Typically, the effervescent agents of the present invention are notsimply introduced into or onto the toilet training pad of the presentinvention without a stabilizing mechanism to ensure the effervescentagents stay in the desired area. The effervescent agents of the presentinvention may be introduced into or onto the liner, absorbent core, oranother layer of the toilet training pad of the present inventionutilizing various methods including, for example, spray coating, slotcoating and printing, or a combination thereof. With spray coating, theeffervescent agents are first thoroughly mixed with a urine-solubleadhesive agent to disperse the effervescent agents throughout theadhesive material. It will be recognized that if an effervescent agentis comprised of separate compounds such as an acid and a base or amixture of acids and a mixture of bases and the effervescent agent is tobe utilized in neat form, care should be taken to ensure the adhesive isnon-reactive with the acid and/or base or mixtures. Further, when andacid/base mixture is utilized as the effervescent agent, typically theacid is separately mixed with an adhesive and the base is separatelymixed with an adhesive and the respective mixtures are applied inseparate layers on the substrate.

The adhesive material can comprise a urine-soluble adhesive which willpartially or completely dissolve upon urination by the wearer and allowthe urine to contact the effervescent agent. Suitable urine-solubleadhesives include, for example, polyvinyl pyrrolidone and polyvinylalcohol, and combinations thereof. After the urine-soluble adhesive andeffervescent agent are thoroughly mixed, they can be applied onto thedesired area of the toilet training pad of the present invention byspray coating, knifing, or roller coating, for example, and allowed todry. The urine-soluble adhesive-effervescent agent mixture adheres tothe liner, absorbent core, or another layer where it is retained untilwetted with urine. Upon urination, the adhesive releases theeffervescent agent such that may release or produce gas and alert orsignal the wearer. Typically, the effervescent/adhesive mixturecomprises from about 5% to about 50% effervescent agent by weight,preferably from about 10% to about 40% effervescent by weight. It willbe recognized by one skilled in the art that the mixture ratio of theeffervescent and adhesive may vary depending upon the materialconstruction upon which the mixture is sprayed. In a particularembodiment, a first layer comprising an effervescent agent and anadhesive are sprayed onto the substrate. After the first layer hasdried, a second layer comprising as adhesive agent is sprayed on top ofthe first layer. This combination of two layers may help ensure that theeffervescent agent does not produce gas prior to urination.

Similar to spray coating, effervescent agents may be introduced into oronto the toilet training pad of the present invention through slotcoating. In slot coating, an adhesive-effervescent mixture as discussedabove is introduced directly onto the desired area of the pad in “slots”or discrete row patterns. Upon urination by the wearer, the adhesiveallows a release of the effervescent agent such that it may produce agas. Slot coating may be advantageous in certain applications where itis not desirable to coat the entire surface with an adhesive. In somecircumstances, an adhesive coating over an entire surface may retardquick absorption of the urine into the absorbent core. When slot coatingis utilized, channels are created where no adhesive is present and urinemay drain quickly. Slot coating may also be advantageous in certainapplications where precise control of the location of the effervescentagent is desired. Typically, the rows of effervescent/adhesive arespaced on the order of from about 0.1 inches to about 3 inches apartfrom each other, preferably from about 0.2 inches to about 2 inchesapart from each other, and most preferably about 0.25 inches apart fromeach other. Generally, the rows are evenly spaced across the surfaceupon which they are applied, but may be spaced in specific patterns withvarying spacing if desired. In a particular embodiment utilizing aneffervescent agent comprised of an acid/base mixture, slot coating canbe utilized to create alternating rows of acid/adhesive—base/adhesive toensure that the acid and base do not react together prior to urination.As described above in regard to spray coating, a second layer ofadhesive may be introduced on top of a first slot-coated layercomprising both an effervescent agent and an adhesive to further ensurethat the effervescent agent does not release gas prior to urination.

The effervescent agents of the present invention can also be introducedonto or into a gas-permeable liner, absorbent core, or another layer ofthe training pad of the present invention through the use of a vacuumdriving force. The effervescent agent is positioned on the liner,absorbent core, or another layer while a vacuum driving force is appliedto the opposite side of the liner, core, or layer to drive theeffervescent agent into the fabric matrix of the liner, core, or otherlayer. Varying degrees of vacuum can be applied depending upon the depththe effervescent agent is to be positioned within the substrate. In thisembodiment, no urine-soluble adhesive is necessary. Once in the fabricmatrix of the pad, the effervescent agent is retained until urinationoccurs at which time the urine contacts the effervescent agent. Thisembodiment is particularly useful for solid or powdered effervescentagents which are applied neat. Alternatively, electrostatic forces orother means may be utilized to stabilize the effervescent agent on thesurface of the liner or core.

In an alternative embodiment of the present invention, the acid and/orbase compounds which may be combined to produce an effervescent agentmay be incorporated into a hydrophilic microsponge material which issubsequently used in combination with the pad of the present invention.The microsponge performs the same function as the microencapsulationshell described above. The hydrophilic microsponge containing theeffervescent agent is introduced onto or into the toilet training pad ofthe present invention as discussed above. Suitable materials comprisingthe hydrophilic microsponge include, for example, acrylate polymers andacrylate copolymers of a hydrophilic nature.

To incorporate either a solid or a liquid acid and/or base into thehydrophilic microsponge material, the acid or base can be introducedinto an suitable volatile, such as an alcohol or water and dissolved.The solution containing the dissolved acid and/or base is contacted withand absorbed into the microsponge material. After absorption, thesolvent is driven off by evaporation or other means known in the art,leaving a dry hydrophilic microsponge material containing the acidand/or base. Because of the structure of the sponge, the effervescentagent is suitably stable as it would need to travel a tortuous path toexit the sponge. The acid and/or base is located in the interstitialspaces in the sponge and, upon flooding of the sponge upon urination, isdriven out of the interstitial spaces by the urine and react to producea gaseous product. The acid and/or base-containing hydrophilicmicrosponges of the present invention may be introduced onto or into thetoilet training pad of the present invention similar to the encapsulatedeffervescent agents discussed above.

Referring now to FIG. 2, there is shown a toilet training article 2 forpurposes of illustration of a toilet training pad 4 of the presentinvention which is attached to the inside of a three-dimensional,disposable, toilet training pant 6. At least a portion of the toilettraining pad 4 contains an effervescent agent in accordance with thepresent invention to alert the wearer when urination has occurred byallowing the effervescent agent to release gas upon urination.

Although the toilet training pad in FIG. 2 is illustrated as part oftoilet training pants, the training pad may also be used in conjunctionwith other garments, such as underwear, diapers, diaper pants, washableor reusable absorbent garments such as cloth training pants, clothdiapers, plastic training pants, or the like. The effervescentcontaining toilet training pad may either be part of the garment as awhole (i.e., integrated into the garment when manufactured) or may be inthe form of an insert which may be permanently or releasably attached toany of the aforementioned garments by the manufacturer or the consumer.If the toilet training pad containing the effervescent agent ismanufactured in the form of an insertable pad, it preferably hasattachment means thereon to allow the consumer to easily attach the padto an undergarment. Suitable attachment means may include, for example,adhesive strips, thermal bonds, ultrasonic bonds, hook and loop typefasteners. This allows the consumer the choice of the type of garment touse with the toilet training pad of the present invention. Also, theconsumer can control when the toilet training pad is used.

Referring again to FIG. 2, the training pant 6 is a three-dimensionalgarment and defines a waist opening 8 and two leg openings 10 and 12. Acrotch region 14 is generally located between the leg openings 10 and 12and comprises that portion of the training pant which, when worn, ispositioned between the legs of the wearer and covers the lower torso ofthe wearer. The crotch region is typically where the toilet training padcontaining the effervescent agent is located. A front waist region 16 ofthe training pants 6 generally extends from the crotch region 14 to afront end 60 of the pants, and a back waist region 20 extends from thecrotch region 14 to a back end 22 of the pants. The training pant 6 alsoincludes an inner surface 24 and an opposite outer surface 26. By way ofillustration only, various materials and methods for constructingtraining pants are disclosed in PCT Patent Application WO 00/37009published Jun. 29, 2000 by A. Fletcher et al; U.S. Pat. No. 4,940,464issued Jul. 10, 1990 to Van Gompel et al.; and U.S. Pat. No. 5,766,389issued Jun. 16, 1998 to Brandon et al., which are incorporated herein byreference. When the training pant is worn, the toilet training pad ispositioned near or against the skin of the wearer and located so thaturine contacts the toilet training pad during urination. The toilettraining pad or toilet training pad area, which may encompass both thecrotch region and the buttocks region, contains the effervescent agentin accordance with the present invention.

In view of the above, it will be seen that the several embodiments ofthe invention are achieved. As various changes could be made in theabove-described toilet training pad without departing from the scope ofthe invention, it is intended that all matter contained in the abovedescription be interpreted as illustrative and not in a limiting sense.

1. An article for use in conjunction with an undergarment in the form ofa pad comprising a pliable substrate and an effervescent agent disposedon the substrate, the effervescent agent comprising a mixture of an acidcompound and a base compound that, upon being contacted with urine,react and produce a gas, the substrate having a body side face and anoutside face, the body side face facing the skin of the wearer when thearticle is worn, the effervescent agent being disposed on the substratein a manner such that when the pad is wetted with urine, theeffervescent agent releases a gas to alert the wearer of urination. 2.The article as set forth in claim 1 wherein from about 0.1 grams toabout 15 grams of effervescent agent is disposed on the substrate. 3.The article as set forth in claim 1 wherein the acid compound is a solidand the base compound is a solid.
 4. The article as set forth in claim 1wherein the mixture comprises substantially stoichiometricallyequivalent amounts of base and acid.
 5. The article as set forth inclaim 1 wherein the mixture further comprises a buffer.
 6. The articleas set forth in claim 1 wherein the gas produced is carbon dioxide. 7.The article as set forth in claim 1 wherein the resulting pH of themixture of the acid compound and the base compound upon being wettedwith urine is from about 4.5 to about 7.5.
 8. The article as set forthin claim 1 wherein the base compound is sodium bicarbonate and the acidcompound is selected from the group consisting of potassium bitartrate,sodium aluminum sulfate, ascorbic acid, lactic acid, glycolic acid,malic acid, tartaric acid, and fumaric acid.
 9. The article as set forthin claim 1 wherein the effervescent agent is encapsulated in a shellmaterial, the shell material being capable of releasing the effervescentagent when wetted with urine.
 10. The article as set forth in claim 9wherein the shell material comprises a material selected from the groupconsisting of ethyl cellulose, starches, sugars, dextrins, andcyclodextrins.
 11. The article as set forth in claim 9 wherein the shellmaterial is urine-dispersible.
 12. The article as set forth in claim 9wherein the shell material is urine-swellable.
 13. The article as setforth in claim 9 wherein the shell material is urine-permeable.
 14. Thearticle as set forth in claim 9 wherein the shell material disintegrateswhen wetted with urine.
 15. The article as set forth in claim 1 whereinthe effervescent agent is disposed on the outside face of the substrate.16. The article as set forth in claim 1 wherein the substrate is oflayered construction and comprises a liner and an absorbent core layer,the liner facing the skin of the wearer when the article is worn, andthe effervescent agent is disposed beneath the liner.
 17. The article asset forth in claim 16 wherein the effervescent agent is disposed on theabsorbent core.
 18. The article as set forth in claim 16 wherein thesubstrate further comprises a superabsorbent layer and the effervescentagent is disposed within the superabsorbent layer.
 19. An article foruse in conjunction with an undergarment in the form of a pad comprisinga pliable substrate and an effervescent agent disposed on the substrate,the effervescent agent comprising a mixture of an acid compound and abase compound that, upon being contacted with urine, react and produce agas, the substrate having a body side face and an outside face, the bodyside face facing the skin of the wearer when the article is worn, theeffervescent agent having a size of from about 5 micrometers to about 40micrometers, and the effervescent agent being disposed on the substratein a manner such that when the pad is wetted with urine, theeffervescent agent releases a gas to alert the wearer of urination. 20.The article as set forth in claim 19 wherein the effervescent agent hasa size of from about 20 micrometers to about 35 micrometers.